The gunman who murdered 20 young pupils in the Connecticut primary school massacre took just five minutes to carry out his killing spree yet managed to fire 154 rounds into two classrooms, it was disclosed on Thursday.

The home that Lanza shared with his mother, Nancy, was found to contain two rifles, at least nine knives, three Samurai swords and 1600 rounds of ammunition

Adam Lanza, who also murdered six staff members at Newtown’s Sandy Hook Elementary last December, had a home arsenal packed with weapons, ammunition and shooting equipment.

A home arsenal ... Police recovered a remarkable haul of weaponry, which even included a seven-foot wooden pole "with a blade on one side and a spear on the opposite side", from Adam Lanza's home. Photo: AP

New details of the massacre, along with inventories of guns, knives, swords and other equipment recovered from the 20-year-old’s house, were made public in search warrant reports that were unsealed by a judge in Connecticut.

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The findings - including photographs of a corpse apparently covered in blood, and a newspaper cutting on a previous school massacre - offered the first official clues to Lanza’s mindset prior to his rampage.

One document disclosed that a friend interviewed by the FBI following the shootings had said that the school, which the gunman had attended as a young boy, was "Adam Lanza’s life".

Shooting massacre ... the child murderer Adam Lanza. Photo: AP

It confirmed that friends also said he "rarely leaves home and considers himself to be a shut-in" and that he was an "avid" player of Call Of Duty, the graphically violent military video game.

The home on Yogananda Street that Lanza shared with his mother, Nancy, was found to contain two rifles, at least nine knives, three Samurai swords and 1600 rounds of ammunition.

Officers also found a gift card from Mrs Lanza to her son that appeared to be for the purchase of another semi-automatic handgun. A military-style uniform was recovered from Lanza's bedroom.

House full of weapons ... the home where Adama Lanza lived with his mother Nancy. Photo: Reuters

Lanza used a semi-automatic assault rifle to carry out America’s second-worst school massacre, before shooting himself with one of two handguns he was carrying. A shotgun and 70 rounds of ammunition were also found in his black Honda Civic, which he had parked outside the school entrance.

In a statement accompanying the released police documents, Stephen Sedensky, a state prosecutor, offered new details of what is believed to have happened in the moments after Lanza blasted his way through the entrance of the school and entered a first-grade classroom.

"It is currently estimated that the time from when the shooter shot his way into the school until he took his own life was less than five minutes," Mr Sedensky said.

Nancy Lanza: mother of school shooter Adam Lanza. Photo: Reuters

"154 spent .223 casings were recovered from the scene’’ after being shot from Lanza’s Bushmaster rifle, the prosecutor added. He then shot himself with his pistol. Lanza was carrying three fresh 30-round ammunition clips for the gun when he killed himself.

Mr Sedensky added that investigations by local and state police were continuing and were expected to be completed by the summer.

Officers disclosed in their reports that on entering Lanza’s home soon after the shootings, they discovered Mrs Lanza, 52, shot dead. "Investigators located a rifle on the floor near the bed," they said.

Over the following three days, they returned to the two-storey property several times to recover a remarkable haul of weaponry, which even included a seven-foot wooden pole "with a blade on one side and a spear on the opposite side".

The recovered firearms were registered to Mrs Lanza, who is believed to have encouraged her two sons to shoot. Numerous targets, holsters, bayonets, training manuals and other shooting equipment were found by officers, along with computer equipment and electronic items, including an Apple iPhone.

Police found "three photographs with images of what appears to be a deceased human covered with plastic and what appears to be blood" and a press cutting on a 2008 shooting at an Illinois university. They also recovered a certificate from the National Rifle Association and several journals, handwritten notes and drawings apparently produced by Lanza. Their contents were not disclosed.

Lanza is said to have suffered from Asperger's Syndrome, the subject of two books - Look Me in the Eye: My Life with Asperger’s, and Born on a Blue Day: Inside the Extraordinary Mind of an Autistic Savant - that were discovered from his home. Another, Train Your Brain to Get Happy, was also found.

Dannel Malloy, the Governor of Connecticut, used Thursday’s release of the police documents to renew his demand for tighter firearms regulations.

"We knew that these weapons were legally purchased under our current laws," said Mr Malloy. "I don’t know what more we can need to know before we take decisive action to prevent gun violence. The time to act is now."

The National Rifle Association, which has come under criticism for its robust response to the killings, on Thursday reiterated that it had no record of Lanza ever having been a member of the pro-gun lobbying organisation.